On the Stats tab, press the Info button. This will list all tournaments found, but omits those that were not used to compute stats. In your case, it should list 41 tournaments.
Then uncheck the box next to "Hide tournaments that were not used to compute statistics". You should now see 176 tournaments. If you don't, it's probably because you've got those 135 missing tournaments in another folder, so the filter isn't filtering them out, it doesn't see them at all. If you do have 176 tournaments, you can now see why they weren't included. The "Status" column gives a brief description, but you can double-click a tournament and get a slightly more descriptive reason why tournament isn't included.